Evaporator and method of operation



Mazmh E3, 1928,

C. F. BRAUN EVAPORATOR AND METHOD OF OPERATION Filed March 14, M922 2 Sheets-Sheet l STEAM /NLET STE/4M OUTLET m m, a m r r eB. o M 0F W n W 6B 5 Nn T 0H n CC MN Mm 6 7 NM a 3 w f, 11| 8 5 w March 13, 1928. 1,662,42

C. F. BRAUN EVAPORATOR AND METHOD OF OPERATION Filed March 14, 1922 2 Sheets-Sheet 2 llyc.

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Patented Mar. 13, 1928.

' UNITED STATES CARL F. BRAUN, F SAN FRANCISCO, CALIFORNIA.

EVAPORATOR AND METHOD OF OPERATION.

Application led March 14, 1922. Serial No. 543,584.

This invention relates to an evaporator and particularly pertains to apparatus for bringing about the distillation of liquids.

In the petroleum industry at the present time itis common practice t bring about the distillation of hydrocarbon liquids by the use of horizontal stills in which the liquid is placed, and where distillation is brought about by the exterior application of heat or the delivery of steam to the body of liquidand at the bottom thereof. In either instance it has been found diiicult when the liquids are at substantially the same boiling point to insure that the various fractions of distillate may be carried oit from the liquid without the possibility of recondensing the fractions and causing them to be again absorbed by the remaining body of undistilled liquid. It is the principal object of the present invention, therefore, to provide an evaporator or still, within which hydrocarbon liquids may be readily evaporated by a method which Will insure that there will be a maximum progressive distillation ofthe various fractions of oil, and at the same time a minimum condensation of the fractions after distillation.

The present invention contemplates the use of a vertical still to which a liquid and a fluid may be delivered and heated, at which time a condition of partial pressure will be created at the evaporating surface of the liquid, the invention further having in mind'a counter circulation of the fiuid and liquid in different paths of travel, whereby condensate and other particleso liquid in suspension will not be carried from the still.

The invention is illustrated b way of example in the accompanying rawings, in which:

Fig. 1 is an enlarged view in central vertical section through the still with which the present invention is concerned, a portion of said still being broken away for the sake of convenience. v

Fig. 2 is an enlar ed transverse section throu h the still ont e line 2-2 of Fig. 1.

Re erring more particularly to the drawing, 10 indicates a Ytubular vertical shell preferably cylindrical in section. The lower end of this shell is formed with a bolting flange 11 adapted to receive bolts 13 which pass through a iiange 14 formed as a part o a cover cap 1 5. The upper end of the shell is formed with an enlarged circumscribing Wall portion 16 by Whlch a semicircular vapor outlet channel 17 and a semicircular oil inlet channel are provided. The upper end of the shell 10 terminates a distance short of the wall portion 16, thus forming an annular opening establishing communication with the central pawage# way through the body of the shell. The terminating end of the wall 16 agrees in configuration and alignment with the main body of the shell and is fitted with a flange 19 to receive bolts 20. These bolts pass through fianges 21 of a dome 22. This dome is provided with a fluid inlet opening 23. The upper end of the dome is fitted with a cover plate 24 secured in position by bolts 25 which pass through flanges 26 and 27 of the plate and the dome respectively. Suitable packing means 28 are interposed between the body of the ldome and the cover plate.

Suspended from the top of the shell isa tube nest 29S This nest of tubes is provided with an upper tube sheet 30 which is `clamped between the upper end of the shell and the lower face of the dome. Suitable packing washers 31 are used to prevent leak-v .age in the joints between the various members.' A plurality of tubes 32 pass through the tube sheet and extend downwardly to pass through a lower ioating tube sheet 33. This sheet is fitted with a cap 34 held in place by bolts 35 and forming a condensate chamber 36. Attention is directed to the fact that theoutside diameter of the tube sheet 33 and the cap 34 are somewhat smaller than the inside diameter-of the cap member 15, thus making it possible for the tube nest to freely float at its lower end and to adjust itself as expansion and contraction takes place in its members.

A condensate drain pipe 37 connects with the bottom of the cap 34 and extends downwardly through the shell cap 15. This pipe is free .to move longitudinally, a tight joint being made between the shell cap and the. pipe by a stuiiing box 38. Y

The oil inlet chamber 18 formed around the upper end ofthe shell body receives a constant supply of oil through an inlet connection '39 as more clearly shown in Fig2. This oil is delivered to the central shell chamber through a pluralit, of nozzles 40. These nozzles extend radial y through the side walls 16 and 10 of the shell and are removably secured in the shell b an outer threaded portion 41. Inlet openmgs 42 are formed through the upper wall portions of each nozzle, to permit the oil to drain from the compartment 18 into the nozzle and to thus pass into the innermost ends ofl the nozzles. The oil delivered to the shell chamber through the nozzle flows directly into a baffle pan 43. By reference to Fig. 1 it will be seen that a plurality of baille pans are used, one substantially agreeing in outside diameter with the inside diameter of the shell as indicated at 43, and pans 44 of much smaller diameter, but larger than the outside sectional dimensions of the tube nest. The tubes 32 pass successively through alternate pans 43 and 44, which pans `act as distributing chambers for the oil and as baflles for a vapor or gas circulating upwardly through the shell. The openings provided in the floor of the pans for the tubes 32 are of somewhat larger diameter than the tubes as indicated at 45, thus insuring that a film of oil will be uniformly created around the outer surface of each of the tubes, said film flowing downwardly along the tubes and through the Hoors of the various pans. Attention is directed to the fact that one or more pans may be disposed above the point of entry of the oil to serve as baffle members and to prevent particles of oil from passing directly from, the shell.-

In operation of the present invention, oil is delivered to the upper end of the shell through the inlet pipe 39, after which it Hows into the semi-c1rcular passageway 18 and then Hows through the main wall of the shell through the nozzles 40. These nozzles feed the oil into a pan 43. This pan will gradually fill up as determined by the rate of How of the incomingoil. The oil will gradually distribute itself over the Hoor of the pan and will encounter the surface of the tubesl 32.

Due to the fact that there is a. small annular passageway 45 formed around. each of the tubes, a thin film ofoil will be applied to the entire cylindrical face of each tube. This oil will gravitate along the tubes toward the bottom of the shell. IVhile this passage of oil is taking place, fluids are Howin in counter directions through the tubes anl around the tubes. The temperatureof the fluid within the tube must be greater than the tem erature of the Huid flowing around the tu e, thus preventing the possibillt of condensation of the surrounding Hui from taking place on the tubes. At the same time this will insure that the thin film of oil which is Howing down t-he tubes will be directly heated through the wall of the tubes by the downwardly flowing Huid in the tubes.

The flowing oil willbe in constant contact .be drained off through the This upwardly Howing Huid which is in most instances steam, is not miscible with oil in -all proportions and at the boiling point of the mixture the sum of the vapor pressures of the two constituents must be equal to the total pressure, while the liquid 1s boiling. The boiling point must therefore be lower than that at ordinary pressure of the two substances because the partial pressure is necessarily smaller than the total pressure which is equal to that of theatmosphere.

By examining the section of applicants still it will be noted that due to the laws of partial pressure distillation will be progressively carried on at diminished pressures so that volatilization of the different fractions lin the series represented by the oil being passed through the still will take place as certain points are reached by the oil in its downward travel. Thus there will be a varying condition of partial pressure and vapor tension throughout the length of the still and the various successively heavier fractions will pass ofl' as the oil Hows towards the bottom of the still while it is moving intoa zone having an atmosphere of practically pure steam approaching the steam inlet 'pipe and while it is continuously flowing along the heated pipes 32. Due

to this arrangement there will be progressive volatilization of the oil, progressive exposure of the oil to the u flowing steam and progressive operation o the various fractions from the oil as the oil Hows downwardly.

It will be further noted that as the oil continues its 'How toward the bottom of the still a quantity of residuum will accumulate. This material will be directly acted upon by the inflowing steam,'thus insuring that al1 possible fractions will pass off from the oil in vapor form. Condensation of the steam may take place in the member 34 and may pipe 37. Expansion of the tube nest wil be com en- /ited for by the sliding joint indicate While I have shown the preferred form of my invention as now known to me, it will be understood that various changes in the combination, construction and arrangement of parts may be made, b those skilled 1n the art, without de artin fii'om the spirit of myinvention as c aime Having thus described my invention, what I claim and desire to secure by Letters Patent is:

A method of distillation in a still consisting of an outer vertically disposed shell surface temperature on the walls of the tubes down through which a plurality of tubes higher than that of the steam in the shell extend, which consists in creating an throughout their length and flowing thin 10 upward flow of steam in the shell and lms of oil on the outer surfaces of the 5 around the tubes, simultaneously internally tubes, to distill the same.

heating the Walls of the tubes, by flowing hot oil downwardly therethrough to maintain a CARL F. BRAUN. 

